The trial of four Jews in Riga reportedly began yesterday in total secrecy, the Jewish Telegraphic Agency learned today from highly reliable sources. The complete news blackout on the trial from the Latvian capital was seen by these sources as a move by Soviet authorities to forestall the kind of protest that erupted last month around the trial of the Leningrad 11 which forced the commutation of death sentences handed down against two Jewish defendants. The JTA had reported Tuesday from Jerusalem that the trial in Riga would begin on Wednesday. This could not then be immediately confirmed and Jewish sources said today that it was still not absolutely certain that the Riga trial had actually started. The Riga defendants have been charged with anti-Soviet activities but the specifies of these alleged activities have never been publicly released by the Soviet authorities. At the same time, the JTA learned that Boris Tsukerman, a prominent Jewish activist in Moscow, finally received his exit visa yesterday and is expected to leave the Soviet Union on Jan. 25. The exit visa for the second Jewish activist, Vitaly Svichinsky, is still being held up but, according to the sources, “there are hopes the Soviet authorities will give him his exit visa by the end of this month.” The sources explained that both men had merely been promised by Soviet authorities that they would be given exit visas but had not actually received them. The sources said it was still not certain why Svichinsky’s exit visa was being hold up. It had been reported earlier that he was scheduled to leave the Soviet Union on Jan. 23.

Tsukerman, a physicist who became an expert in Soviet law and who has been challenging the Soviet regime in its own courts on issues involving government censorship of private mail, has been described by sources as a liaison between Jews who want to leave the Soviet Union and Jewish and non-Jewish scientists and intellectuals who have been chafing under official repression. Both Tsukerman and Svichinsky and their families intend to emigrate to Israel, according to sources. Meanwhile, according to information reaching London from Riga. Margarita Shpilberg, the wife of Arkady Shpilberg who is one of the four Riga Jews on trial, has given birth to a daughter which was named Yocheved, Since the birth of the daughter, Mrs. Shpilberg has been desperately trying to secure permission to see her husband to show him their child but all of her appeals to date have been rejected. She is not even certain whether or not he knows about the birth of their daughter. Shpilberg, 23, an engineer, had applied for permission to emigrate to Israel. The other three Riga Jews on trial are: Mikhail Shepshelovich, 27, a bachelor; Ruth Aleksandrovich, 23, a nurse, and Boris Martsier, 20.